Physical layer security which safeguards data confidentiality based on the information-theoretic approaches has received significant research interest recently. The key idea behind physical layer security is to utilize the intrinsic randomness of the transmission channel to guarantee the security in physical layer. The evolution towards 5G wireless communications poses new challenges for physical layer security research. This paper provides a latest survey of the physical layer security

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... on various promising 5G technologies, including physical layer security coding, massive multiple-input multiple-output, millimeter wave communications, heterogeneous networks, non-orthogonal multiple access, full duplex technology, etc. Technical challenges which remain unresolved at the time of writing are summarized and the future trends of physical layer security in 5G and beyond are discussed. Y. Wu is with Considering the potential of physical layer security for 5G wireless communications, the opportunities and challenges on how the innovative 5G technologies achieve a high security level at the physical layer deserves to receive more attention from the research community. The purpose of this paper is to provide a comprehensive summarization of the latest physical layer security research results on the key technologies of 5G wireless networks. In particular, we focus on the following typical technologies: 1) Physical layer security coding: Although the first physical layer security code appears around 1970s, to design explicit security codes which can be used in practical communication systems is still challenging. We review the state of art of three important physical layer security codes, including low-density parity-check (LDPC) codes, polar codes, and lattice codes. 2) Massive MIMO: Deploying large antenna arrays significantly increases the spatial dimension of wireless 0733-8716 (c)